In line with a communication technique, services provided by a mobile communication system is growingly evolving into diversification of a packet data transmission/reception service for transmitting a large quantity of data, a multimedia broadcast service, and the like, as well as a voice communication service.
A third-generation communication service such as WCDMA, currently on service, allows for a transmission and reception of a large quantity of data, as well as voice data, at a high transfer rate, and in order to create an evolved network having a broader bandwidth in consideration of an anticipated rapid increase in data traffic, standardizations of a long-term evolution (LTE) network, IEEE802.16m, and the like, are being actively ongoing.
In particular, the IEEE 802.16m is aimed at developing a standard that can satisfy the requirements of an IMT-Advanced system while maintaining compatibility with the existing 802.16 standard-based terminal (or user equipment) and base station equipment.
The thusly evolved IMT-Advanced communication system is a broadband wireless access communication system, featuring that it has an extensive service area and supports a fast transfer rate. In order to support a broadband transmission network at a physical channel, the broadband wireless access communication system employs orthogonal frequency division multiplexing (OFDM) and orthogonal frequency division multiplexing access (OFDMA). In the OFDM/OFDMA schemes, a physical channel signal is transmitted and received by using a plurality of subcarriers, thus enabling high speed data communication.
FIG. 1 illustrates an uplink (UL) and downlink (DL) frame structure of a broadband wireless access communication system employing the OFDM/OFDMA schemes.
With reference to FIG. 1, the uplink and downlink frame structure includes areas of a preamble 101, a frame control header (FCH) 102, a DL-MAP 103, a UL-MAP 104, and a plurality of data burst areas.
A preamble sequence, a synchronous signal, for acquiring mutual synchronization between the base station and the terminal is transmitted through the preamble 101 area, channel allocation information and channel code information related to the DL-MAP 103 are provided through the FCH 102 area, and channel allocation information of a data burst in downlink and uplink is provided through the DL/UL-MAP 103 and 104 area. A guard time for discriminating the frames is inserted between an uplink frame and a downlink frame. A TTG (Transmit/received Transition Gap) is a guard time between downlink bursts and subsequent uplink bursts. An RTG (Receive/transmit Transition Gap) is a guard time between the uplink bursts and subsequent downlink bursts.
The IMT-Advanced system is required to support various bandwidths, and in particular, IEEE802.16m, whose standardization is currently proceeding, defines bandwidths such as 5 MHz, 7 MHz, 8.75 MHz, 10 MHz, 20 MHz, etc., as bandwidths of a system channel. However, currently, the IMT-Advanced system does not define a substantial frame structure, and in particular, in case of IEEE802.16m, if frames are individually designed for the respective bandwidths, the system complexity would increase. In addition, the frame structure differs when the length of the cyclic prefix (CP) of the frame is variably configured, and in this case, when a single communication system uses both frame structures each having a different CP length, a problem arises in that the interference between neighboring cells occurs.